Genetic variation in a maize population of RILs: I- Heritability study of the eco-physiological and numerical determinants of grain yield

D'ANDREA, K.E.; SECO, A.V.; GALIZIA, L.A.; MANDOLINO, CECILIA; CIRILO, A.G.; OTEGUI, M.E.

Bento Goncalves

Congreso; VI International Crop Science Congress; 2012

International Crop Science Society

Research on the physiological and numerical determinants of maize (Zea mays L.) grain yield is scarce in inbred lines as compared to hybrids, although these traits could improve selection efficiency. The development of maize germplasm with good performance under nitrogen stress implies a detailed knowledge of the physiological aspects involved, and of the interaction among promising traits and the target environment. The aim of this work was to study the genotypic variation for maximum leaf area (LAIMAX), fraction of radiation interception by the canopy (fIPAR), total shoot biomass, harvest index (HI), grain yield per plant (PGY), anthesis-silking interval (ASI), kernel number per plant (KNP), kernel weight and prolificacy. We phenotyped these traits for a collection of 180 recombinant inbred lines (RILs) derived from two contrasting parental inbreds (B100: American semident; LP2: Argentine flint). The collection, both parentals and a tester line were grown under irrigation during two seasons (2009-2010 and 2011-2012). The experimental layout was a completely randomized block design with two replicates. The results showed that (i) there was significant genotypic variability (Pe.g. KNP) could be an advantage in less favorable environments, especially considering their early quantification as compared to grain yield. We identified lines of high and low grain yield (located on the topmost and bottommost 5% of the distribution). Inbreds in the uppermost 5% for PGY were those within the uppermost quartile for plant biomass, LAIMAX, HI and KNP. These results demonstrate the importance of enhanced light capture, achieved through a high LAI, in determining plant biomass at maturity and, therefore, PGY. This characterization is a starting point for genetic studies based on molecular marker associations.